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OK not an iceberg at all, but part
of a land-based snow slope. In the spring when the winters snow begins
to melt, water flows across the top of glaciers and snow slopes carrying
with it dissolved nutrients in the melt water. In these conditions,
algae grows within the top layer of the ice or snow catching the goodies
as they flow by and taking advantage of the extra energy from the longer
days and stronger sunshine.
In this case the algae is predominantly
a red-coloured species, but further down the slope, green and blue-green
colours are discernable. This is relatively short-lived spring phenomena
as soon the very snow and ice layer that the algae are living in will
melt and the algae will flow down to the sea with the water that provides
them with their nourishment. It is not unusual to see distinctly red,
green or blue-green topped ice bergs in the spring as a result of the
growth of such algae.
There are over 300 species of such
algae that live in such harsh and cold conditions. The red colour is
a protective chemical (carotenoids such as astaxanthin) that the alga
produces against exceptionally high concentrations of visible and ultra
violet light that bounces off the snow and ice surfaces and so saturates
them to a point where it become harmful and destructive. Such algae
are also found in other parts of the world, often in high mountains
where extra u-v light due to the thinner atmosphere and again increased
light scattering by ice and snow requires protection by similar pigments.
Sometimes, walking across such an area
will leave behind red footprints as the algae are concentrated by the
walker as the snow is crushed, and sometimes there will be a a faint
smell of fresh watermelon accompanying the phenomena.
Paul Ward - Pentax equipment, 28mm
lens, 35mm film, K64. This picture may not be copied or used in
any manner without prior written permission. |